Automatic controls for room air conditioning unit



Jan. 1, 1963 L. w. ATCHISON AUTOMATIC CONTROLS FOR ROOM AIR,CONDITIONING UNIT Filed D90. 22, 1960 United States Patent Ofitice 3,970,972 Patented Jan. 1, 1963 3,070,972 AUTOMATI CQNTROLS FOR ROOM AIR CGNDITIGNING UNIT Leonard W. Atchison, Louisville, Ky., assignor to General Electric Company, a corporation of New York Filed Dec. 22, 196i), Ser. No. 77,665 2 Claims. (Cl. 62-180) The present invention relates to and has for its principal object the provision of an improved room-air condi tioning unit of the self-contained type incorporating an arrangement for substantially reducing the fan noise produced by such a unit when the temperature of the room air is such as to satisfy the thermostat setting of the unit and the refrigeration system is, therefore, not in operation.

According to the present invention there is provided an air conditioning unit of the self-contained type including a case adapted for mounting in an outer wall of a room and having compartments therein communicating respectively with room air and outdoor air. The unit includes a refrigeration system having a pair of heat exchangers and a condenser arranged in refrigerant flow relationship. Indoor and outdoor fans are provided for circulating separate streams of air from inside the room and from the outside respectively over the heat exchangers of the unit. A temperature control means is provided within the unit for energizing and de-energizing the refrigeration system according to the temperature of the air stream entering the unit from the room. Switch means, also actuated by the temperature control means, are provided for cycling the indoor fan from a high or other normal operating speed, whenever the refrigeration system is in operation, to a very low speed operation whenever the refrigeration system is de-energized.

For a better understanding of the invention, reference may be had to the accompanying drawings in which:

FIG. 1 is a perspective view showing an air conditioning unit of a self-contained type having the air temperature control of the present invention;

FIG. 2 is a diagrammatical view illustrating the automatic fan speed control of the present invention; and

FIG. 3 is a diagrammatical view illustrating a fan speed control arrangement as applied to a heat pump.

Referring to FIG. 1, there is shown an air conditioning unit of the self-contained type adapted for mounting in a window or opening in the outer wall of an enclosure. The unit is enclosed within a case 2 which, in the illustrated embodiment of the invention, is divided by a barrier 3 into a pair of separate compartments, hereinafter referred to as the inner or evaporator compartment 4 and the outer or condenser compartment 6. The unit is provided with a pair of heat exchangers 7 and 8 mounted respectively within the inner and outer compartments 4 and 6. The heat exchangers 7 and 8 are connected in refrigerant flow relationship by suitable tubing to a compressor 9, which is also disposed in the outer or condenser compartment 6.

In those types of air conditioning units normally utilized for cooling an enclosure, the heat exchanger 7 is operated as an evaporator to extract heat from the air circulated through the evaporator compartment 4 and the heat exchanger 7 from within the enclosure. The heat exchanger 8 is operated as a condenser and discharges heat taken up by the refrigerant flowing through the evaporator 7 to the outdoor air circulated through the outer compartment 6. Suitable means are provided, such as the capillary tube 10 (see only in FIG. 2), for providing a pressure drop between the evaporator 7 and the condenser 8 to promote vaporization of the refrigerant flowing from the condenser 8 to the evaporator 7.

In order to circulate air streams through the inner and outer compartments 4 and 7, there are provided a pair of fans 11 and 12 mounted respectively within the inner and outer compartments and arranged to be driven by a common motor 13 which may be mounted on the barrier '3 of the unit; Outside air is circulated over the condenser 8 by the fan 12 and flows toward the barrier 3 where it is diverted upwardly and then discharged back to the outdoors through suitable outlet openings 5 in the rear of the casing. This air stream extracts heat from the condenser 8. The evaporator fan 11 pulls a stream of air from within the enclosure through the heat exchanger or evaporator 7 into the inner compartment 4. This air is directed rearwardly against the barrier 3 and diverted upwardly along the barrier to be discharged back into the enclosure again through the upper portions of the unit. Suitable ducting is provid within the casing 2 to promote the flow of air into and out of the respective compartments.

Many of the air conditioning units of the-self-contained type now on the market provide a temperature control means or thermostat control for controlling the operation of the refrigeration system according to the t mperature of the air flowing through the evaporator compartment from the room. In the illustrated embodiment of the invention, a temperature control means or a thermostat 14, of a type well known in the market for sensing the temperature of the air, is provided on a control panel 15 on the front of the air conditioning unit. The thermostat 14 is adjustable over a wide range to permit the occupants of the room to select a satisfactory temperature for the air within the room. The temperature control means includes a temperature responsive element or bulb 16 disposed in the air stream flowing into the evaporator compartment 4 so that the bulb 16 senses temperature conditions of the air flowing thereover. The bulb is connected by means of a tubing 17 to a conventional fluid type responsive member or bellows 18 (shown in FIG. 2) and forms with these components a conventional fluid type thermostat. The bulb l6, tubing 17, and bellows 18 together provide a closed chamber for an expansible liquid or vapor. As is well understood in the art, the pressure within the bellows member 18 is a function of the temperature of the bulb 16 and this pressure causes the bellows 18 to operate switching means in the thermostat adapted to energize or d energize the refrigeration system. As will be hereinafter explained, movement of the bellows 18 also modifies the operation of the fan motorsimultaneously with the energization or deenergization of the refrigeration system.

As may be seen in FIG. 2, which illustrates in schematic form the above-described air conditioner, power is supplied to the components of the air conditioning unit through the power lines marked L1 and L2. L2 forms a line having leads connecting with the compressor 9 and the fan motor 13 and L1 completes the circuit through these units through the thermostat, generally designated 14 and included within the dotted line portion of FIG. 2. During normal operation of the air conditioning unit, air circulated over the evaporator 7 by the fan 11 causes the bulb 16 to energize and deenergize the compressor 9 according to the temperature sensed by the bulb 16. When the temperature of the bulb 16 is such as to call for cooling of the air passing thereover, the expansible member or bellows 18 moves the compressor switch 21 across the contacts 22 and 23 thereby completing the circuit across the power lines L1 and L2 through the compressor. At the same time that the switch 21 is moved across the contacts 22 and 23, a second or fan switch means 24, also energized by the bellows 18, is moved into a first position in which it engages contacts 26 and 27 thereby completing a first or 'the line 32 and reactance 33.

see ers high speed fan circuit, including line 28, to energize the fan motor 13. When the fan circuit is energized in this manner, the fan motor 13 operates at its normal or other selected operating speed.

Whenever the temperature of the room air, tlowing over the temperature sensing bulb 16, drops below a predetermined temperature set on the thermostat 14 by th temperature control knob 1? on the front of the unit, then the bellows moves the compressor switch 21 away from its contacts 22 and 23, thereby de-energizing the compressor 9. Simultaneously with the movement of the switch 21 away from contacts 22 and 23 the fan switch 24 is moved to a second position in which it disengages contacts 26 and 27 and is connected across contacts 29 and 31. This completes a second circuit or low speed fan circuit leading to the fan motor 13, including When the reactance 33 is connected into the fan motor circuit there is a great reduction in the fan speed and, thus, a great reduction in the noise output of the fans. may be used, such as an inductive or capacitive reactance or some combination of these. it is contemplated, however, that the reactance be sufiicient to reduce the fan speed very drastically so that there is little or no audible noise output from these fans. It is only necessary to have sufiicient fan speed to move a very small quantity of room air over the bulb 16 so that control of the room temperature may be adequately maintained. This may be a fan speed of only 200 to 599 r.p m. as compared to the normal fan speed of 1000 to 1600 r.p.m. It is probably desirable to utilize an inductive type reactance, capable of reducing the fan speed very drastically, without too great a power loss or heat dissipation in the reactance itself. In the illustrated embodiment of the invention, the reactance 33 is shown external to the a motor 13. However, it is very likely that other means such as inductive windings in the stator of the fan Inotor itself could be energized by the second circuit in order to reduce the speed of the fan motor.

Referring now to FIG. 3 there is shown an arrangement of the invention as applied to an air conditioning apparatus designed for both heating and cooling air from an enclosure. The refrigeration system of this apparatus contains a reversing valve 33 which connects to the compressor 9 through suction inlet and exhaust lines 36 and 37 respectively. The reversing valve may be conditioned to selectively direct high pressure discharge gas from the compressor either into the line 39 leading to the outer heat exchanger 8 or into the line 40 leading to the inner heat exchanger 7. Whenever the reversing valve 38 discharges hot gas into the line n leading to the heat exchanger 7, which is the heat exchanger exposed to room air, the unit then heats air from the enclosure. And correspondingly, when hot discharge gas is directed into the line 39 leading to the outer heat exchanger 8, the

unit functions to cool air from the enclosure. Means such as the knob 38a on the front of the unit is provided for selectively adjusting the reversing valve 35 to operate the unit on a heating or cooling cycle according to the wishes of the operator. The reversing valve 38 may either be manually moved to its respective positions or may be operated by a solenoid which is energized when the operator turns the knob 38a. Reversing valves and the operation thereof are well known in the art and a more detailed description thereof is not believed necessary for a full understanding of the present invention.

In order to cycle the fan motor 13 to low speed operation whenever the refrigeration system is de-energized, there is provided a temperature control means or thermostat 14a which may also be conditioned by the control knob 19 on the front of the unit to cycle the refrig eration system on and off according to temperature rises in the enclosure as well as according to temperature decreases in the air from the enclosure. Thermostats adapted for this purpose are well known in the art and may,

Any type of reactance for example, include a second temperature sensing means, such as the bulb 16a, tube 17a, and bellows 18a for actuating the switches of the thermostat whenever the thermostat is conditioned to control the refrigeration system according to temperature decreases in the enclosure air stream. It should be understood that FIG. 3 is only a schematic diagram and that bulbs 16 and 16a and their associated bellows 18 and 18a operate the thermostat switches independently from each other and, as stated above, the knob 19 may be employed to condition the thermostat so that the switches are responsive to one or the other of the bulbs, depending upon whether the conditioner is to be operated for cooling or heating purposes. Whenever the thermostat 14a is conditioned to operate in accordance with conditions sensed by the bulb 16a, the compressor switch 21 disengages from contacts 22 and 23 to deenergize the compressor 9 whenever the temperature in the enclosure rises above the predetermined temperature set on the thermostat. As in the operation of the arrangement shown in FIG. 2, the fan switch 24- also disengages contacts 36 and 27 and moves across contacts 29 and 31 when the thermal sensing bulb 15a senses a temperature above that set on the thermostat. This electrically connects the fan motor 13 into its second or low speed circuit in which the reactor 33 is placed in series with the fan motor 13. The fan then operates at reduced speed greatly reducing the air flow through the inner compartment and the noise of the fan is reduced accordingly. When the room temperature as sensed by the bulb 16a drops, then the bellows 18a moves the switch 21 across the compressor circuit circuit contacts 22 and 23 and simultaneously moves the switch 24 across the high speed contacts 26 and 27 to connect the fan motor 13 into its high speed circuit. Of course, during operation of the unit on the cooling cycle, the thermostat 14a is conditioned to operate in the manner previously described with respect to the embodiment shown in FIG. 2 and bellows 18 and bulb 16 controls the movement of the fan switch 24 and compressor switch 21. it will be noted that air at a very reduced velocity always flows through the unit when the room temperature has satisfied the conditions set on the thermostat. This permits continual sensing of the room temperature and gives complete control of the temperature of the room air, yet permits operation of the fan 13 at reduced speed whenever the total capacity of the unit is not required and thereby greatly reduces the overall noise output of the unit at these times.

By the present invention there has been provided an improved air conditioning unit of the self-contained type in which the temperature sensing device utilized for cycling the refrigeration system on and oil, according to the temperature of the room air entering the unit, also varies the operating speed of the fan motor simultaneously with the on and off cycles of the refrigeration system.

While in accordance with the patent statutes there has been described what at present is considered to be the preferred embodiments of the invention, it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is, therefore, the aim of the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An air circulating apparatus for conditioning the air within an enclosure comprising a casing, a barrier dividing said casing into an inner compartment exposed to air from the enclosure and an outer compartment exposed to air from outdoors, a refrigeration ystem mounted in said casing including a compressor connected in refrigerant flow relationship with an inner heat exchanger mounted in said inner compartment and an outer heat exchanger aovaozz mounted in said outer compartment, reversing means in said refrigeration system for reversing the flow of refrigerant to said heat exchangers thereby to selectively operate either of said heat exchangers as an evaporator while operating the other heat exchanger as a condenser to heat or cool air flowing from said enclosure through said inner compartment, means for selectively conditioning said reversing means to operate said unit on a heating or cooling cycle, fans for circulating separate air streams from within said enclosure and from the outdoors over said inner and outer heat exchangers respectively, at least one motor for driving said fans, means for conditioning said temperature control means to energize said refrigeration system according to rises in the temperature of said air stream entering said inner compartment when the unit is conditioned for operation on the cooling cycle and for energizing said refrigeration system according to decreases in the temperature of said air stream entering said inner compartment when said unit is conditioned for operating on the heating cycle, fan switch means movable between a first position wherein it electrically connects said fan motor into a high speed circuit to a second position wherein it connects said fan motor into a low speed fan circuit, means associated with said temperature control means for moving said fan switch means to said first position when said refrigeration system is energized by said temperature control means and for moving said fan switch means to said second position when said refrigeration system is de-energized by said temperature control means thereby greatly reducing the noise of said fans when said refrigeration system is de-energized.

2. An air conditioning apparatus for conditioning the air within an enclosure comprising a casing; a barrier dividing said easing into an inner compartment and an outer compartment, a reversible refrigeration system mounted in said casing including a compressor, a reversing valve and a pair of heat exchangers connected in reversible refrigerant flow relationship; one of said heat exchangers being mounted in said inner compartment and the other heat exchanger being mounted in said outer compartment; fans for circulating separate air streams from within said enclosure and from the outdoors over said heat exchangers in said inner and outer compartments; at least one motor for driving said fans; means for conditioning said reversing valve to operate said inner heat exchanger as a condenser for heating said air stream from said enclosure; a temperature control means responsive to the temperature of said air stream being circulated into said inner compartment from said enclosure; said temperature control means being adaptable to energize said refrigeration system when the temperature of said air stream entering said inner compartment is below a predetermined temperature and for deenergizing said refrigeration system when the temperature of said air stream entering said inner compartment is above a predetermined temperature; a fan switch movable between first and second positions for connecting said fan motor into a high speed circuit or a low speed circuit respectively; and means associated with said temperature control means for moving said fan switch to said first position when said temperature of said air stream is below said predetermined temperature and for moving said fan switch to said second position when said temperature of said air stream is above said predetermined temperature so that said fans are operated at reduced speed and produce correspondingly less noise when the temperature of the air stream from the enclosure is above said predetermined temperature and heating thereof is not required.

2,195,924 Hoesel Apr. 2, 1940 Dickey Oct. 24, 1944 

1. AN AIR CIRCULATING APPARATUS FOR CONDITIONING THE AIR WITHIN AN ENCLOSURE COMPRISING A CASING, A BARRIER DIVIDING SAID CASING INTO AN INNER COMPARTMENT EXPOSED TO AIR FROM THE ENCLOSURE AND AN OUTER COMPARTMENT EXPOSED TO AIR FROM OUTDOORS, A REFRIGERATION SYSTEM MOUNTED IN SAID CASING INCLUDING A COMPRESSOR CONNECTED IN REFRIGERANT FLOW RELATIONSHIP WITH AN INNER HEAT EXCHANGER MOUNTED IN SAID INNER COMPARTMENT AND AN OUTER HEAT EXCHANGER MOUNTED IN SAID OUTER COMPARTMENT, REVERSING MEANS IN SAID REFRIGERATION SYSTEM FOR REVERSING THE FLOW OF REFRIGERANT TO SAID HEAT EXCHANGERS THEREBY TO SELECTIVELY OPERATE EITHER OF SAID HEAT EXCHANGERS AS AN EVAPORATOR WHILE OPERATING THE OTHER HEAT EXCHANGER AS A CONDENSER TO HEAT OR COOL AIR FLOWING FROM SAID ENCLOSURE THROUGH SAID INNER COMPARTMENT, MEANS FOR SELECTIVELY CONDITIONING SAID REVERSING MEANS TO OPERATE SAID UNIT ON A HEATING OR COOLING CYCLE, FANS FOR CIRCULATING SEPARATE AIR STREAMS FROM WITHIN SAID ENCLOSURE AND FROM THE OUTDOORS OVER SAID INNER AND OUTER HEAT EXCHANGERS RESPECTIVELY, AT LEAST ONE MOTOR FOR DRIVING SAID FANS, MEANS FOR CONDITIONING SAID TEMPERATURE CONTROL MEANS TO ENERGIZE SAID REFRIGERATION SYSTEM ACCORDING TO RISES IN THE TEMPERATURE OF SAID AIR STREAM ENTERING SAID INNER COMPARTMENT WHEN THE UNIT IS CONDITIONED FOR OPERATION ON THE COOLING CYCLE AND FOR ENERGIZING SAID REFRIGERATION SYSTEM ACCORDING TO DECREASES IN THE TEMPERATURE OF SAID AIR STREAM ENTERING SAID INNER COMPARTMENT WHEN SAID UNIT IS CONDITIONED FOR OPERATING ON THE HEATING CYCLE, FAN SWITCH MEANS MOVABLE BETWEEN A FIRST POSITION WHEREIN IT ELECTRICALLY CONNECTS SAID FAN MOTOR INTO A HIGH SPEED CIRCUIT TO A SECOND POSITION WHEREIN IT CONNECTS SAID FAN MOTOR INTO A LOW SPEED FAN CIRCUIT, MEANS ASSOCIATED WITH SAID TEMPERATURE CONTROL MEANS FOR MOVING SAID FAN SWITCH MEANS TO SAID FIRST POSITION WHEN SAID REFRIGERATION SYSTEM IS ENERGIZED BY SAID TEMPERATURE CONTROL MEANS AND FOR MOVING SAID FAN SWITCH MEANS TO SAID SECOND POSITION WHEN SAID REGRIGERATION SYSTEM IS DE-ENERGIZED BY SAID TEMPERATURE CONTROL MEANS THEREBY GREATLY REDUCING THE NOISE OF SAID FANS WHEN SAID REFRIGERATION SYSTEM IS DE-ENERGIZED. 